In this article I will talk about the differences between Temporary Table and Table variable in SQL Server.

The differences between Temporary Table and Table variable in SQL Server are as follows.

1. The names of Temporary tables begin with the ‘#’ sign and are defined as a temporary table, while the names of Table variables begin with the ‘@’ sign and are defined as a temporary variable.
2. Temporary tables are generally used for large datasets, while Table variables are only suitable for small datasets.
3. Table variables are faster than Temporary tables because they are stored in memory and do not require disk I/O. However, when used to store large datasets, Temporary tables can offer better performance.
4. Temporary tables can be used to store data beforehand and then perform many operations on that data. Table variables, on the other hand, are used to use data only once.
5. In the Temporary table, it is defined using the CREATE TABLE statement, while the Table variable is defined using the DECLARE statement.
6. The name of a Temporary table variable can be up to 128 characters, and Table variables can be 116 characters.
7. Temporary table and Table variables both support unique key, primary key, control constraints, Not Null and default constraints, but Table variables do not support Foreign Key.
8. We can remove Temporary tables using Drop or Truncate command. We cannot use the Drop or Truncate command for temporal variables.
9. We can only declare table variables using the Declare statement, but Temporary tables can be created using the Create Table and Select Into commands.
10. Table variables and Temporary tables support ROLLBACK, but Table variables retain data after ROLLBACK.
11. Global Temporary tables retain data after creation and can be used in other sessions, even if the database connection is terminated. However, Table variables are destroyed when the session is terminated or the resource is released.

Good luck to everyone in business and life.

The post What are the Differences Between Temporary Table and Table Variable in SQL Server? first appeared on MSSQL Query.

Under this title, we will examine the differences between Temporary Table and Table Variable in SQL Server.

In some cases, such questions may come up in job interviews in SQL Server. It will always be useful for you to learn the following items.

1. While Temporary Table is created with # sign, Table Variable is also created with @ sign.
2. After the Temporary Table is created, we can perform DDL operations. We will be able to add a new column. Table Variable does not support DDL commands such as ALTER, CREATE, DROP.
3. Temporary Tables are kept in TempDB. Table Variable is stored as In – Memory.
4. It supports the Temporary Table Transaction structure. Table Variable does not support Transaction structure.
5. While user-defined functions (UDF) are not allowed in Temporary Tables, it is allowed to use user-defined functions (UDF) in Table Variables.
6. Temporary Tables support indexes, and indexes created with Primary Key and Unique Key are also supported. Indexes are not supported in Table Variables.
7. Temporary Tables are accessible in the environment in which they are defined. If it is desired to be accessible from all environments globally, ‘##’ should be used instead of ‘#’ when creating the Temporary Table. It supports both local and global access, depending on the type of creation. Table Variables can be accessed from the defined environment. Global access type is not available.
8. Tables of Table Variable type work much faster than tables of Temporary Table type.
9. Temporary Table; While it can be used in nested stored procedures, Table Variable; It cannot be used in nested stored procedures.
10. While you can create Temporary Table with SELECT INTO, you cannot create Table Variable with SELECT INTO.
11. If there is a Temporary Table in the Stored Procedure, the stored procedure is recompiled every time, while if there is a Table Variable, the recompile process does not occur.
12. Temporary Table works better than Table Variable in large tables.
13. If the number of rows is less than 100, Table Variable is usually used. If the number of rows is over 100, it is better to use Temporary Table.

Good luck to everyone in business and life.

The post Differences Between Temporary Table and Table Variable in SQL Server first appeared on MSSQL Query.